This invention relates to packaging and, more particularly, to packages of perishable articles such as hen's eggs.
It is well known that many foods tend to deteriorate to a greater or less degree in an atmosphere of air. Eggs, for example, are particularly susceptible to the adverse effects of oxygen in the atmosphere and begin to deteriorate immediately upon being laid. Among the factors believed responsible for the deterioration and loss of palatability of eggs are: (1) evaporation of water through the shell; (2) escape of carbon dioxide through the shell, and (3) a change in pH. Carbon dioxide and bicarbonates of sodium and potassium comprise a buffer system within the albumen of the egg. With the loss of carbon dioxide and the resulting reduction in concentration of bicarbonate ions, the buffer system progressively becomes disorganized and the pH of the system tends to rapidly increase from approximately neutral to an alkaline value. It is therefore desirable that the eggs be insulated from the atmosphere as soon as possible after they are laid to protect them from the air and also to prevent escape of moisture and carbon dioxide emitted by the egg.
It is also known that hen's eggs sometimes contain any of various salmonella bacteria, many of which, when ingested, can cause serious disease. A 1998 assessment issued by the Department of Agriculture predicted that one in 20,000 eggs would have salmonella. In recent years, methods have been developed to pasteurize eggs in the shell to eliminate the risk of salmonella. The known methods rely on hot water baths to sterilize an egg without cooking it and deliver an egg said to look, cook and taste the same as an unpasteurized egg. The same result is attainable when hot air is used to sterilize an egg in the shell--after it has been packaged in a sealed container. For this to be done, the package must be able to withstand the temperatures necessary for pasteurization without compromising the seal of the package.
Accordingly, it is an object of the present invention to provide a novel and economical package for eggs which reduces their tendency to deteriorate.
Another object is to provide such a package which protects the contained eggs against damage from normal impacts.
Still another object is to provide such a package which permits visual inspection of the contents without opening the package.
Another object is to provide an egg pack wherein a plurality of eggs are effectively individually packaged so that one or more eggs may be removed without destroying the protection of the remaining eggs.
Another object is to provide such a package which has a relatively large display area on which to print a description of the contents.
Still another object is to provide such a package which will allow it to be subjected to hot air at a temperature sufficient to sterilize a contained egg without cooking it.